The present invention relates to roller tracks for moving large tubes or pipes through a tempering furnace.
Large pipes are often tempered at about 1000.degree. C., for example, in a gas furnace. The pipes must be moved into and out of the furnace and one uses here a roller track constructed from plural pairs of rollers. The pairs of rollers are spaced along the track by a distance which is equal to about one quarter of a normal pipe length.
It was found that during heating the pipe is quite often damaged in the furnace by the last rollers. In particular, the rollers score the pipes and carve grooves or groove-like indentations into the pipe's surface. The reason for the last rollers in the track doing the damage is that the pipe has maximum temperature when engaging these last rollers and the strength of the pipe is reduced accordingly. As the particular temperature to which the pipe is subjected is deemed necessary for carrying out the particular tempering process, it is not possible to just reduce the temperature.